The present invention relates to an image processing device carrying out image processing corresponding to image data or a drawing command, generated by various types of applications.
Digitization has spread to the field of printing processing, and the trend toward DTP (Desktop Publishing) has advanced. In this way, a page layout is generated by making, treatment (trimming), editing, and the like of an image in a processing device such as a personal computer, a work station, or the like. A film is prepared on the basis of this page layout, or a printing plate for printing is prepared by directly writing onto a printing plate (CTP: Computer to Plate).
On the other hand, when proofing is carried out in advance of printing or the like which uses an actual printing plate, a page layout is displayed on a monitor by using the WYSIWYG function, or is printed out by a printout device such as a laser printer, a page printer, or the like.
In printing using a printing plate, a thinner line can be specified (represented) than in printing using a printer. Namely, resolution of 2400 dpi or more can be obtained in printing using a printing plate, whereas the resolution is about 400 dpi to 600 dpi in printing using a printer.
Accordingly, even in the case of a thin line which can be specified in printing using a printing plate, there are cases in which the thin line disappears or becomes blurred on a printed matter (a printing sheet) by using a printer.
Therefore, in Japanese Patent Application Laid-Open (JP-A) No. 6-231238, a thin line is converted to a line having a thickness which can be outputted by a printer, and occurrences of disappearance, blurring, and the like of the thin line are thereby prevented at the time of printing by using a printer.
However, a printed matter, which is prepared by carrying out printing processing by converting a thin line which cannot be represented by a printer to a thin line which can be represented by the printer, is different from a printed matter prepared by using a printing plate. For example, even in the case of a line image of a thickness by which blurring and the like occur when a printing plate is used, the line image is represented as a line image in which blurring does not occur, on a printed matter prepared by using a printer.
Further, in a case in which a thin line which cannot be outputted by a printer is merely converted to a thickness which can be outputted by the printer, there are cases in which even thin line images, at which blurring or the like occurs at the time of printing by using a printing plate, are outputted. Therefore, because it cannot be verified how the image will appear in the printed matter, accurate proofing is of course difficult, and what portions are different is unclear until a printing plate is prepared and printing processing is actually carried out.